Development of a sediment generation and routing model for irrigation return flow. Annual report

The primary purpose of this project is to develop a sediment modeling package for use with surface irrigation return flow. A primary goal is to develop operational computer tools requiring minimal data input for predicting water quality with respect to sediment. Defined objectives for the model package were: (1) The model package should be capable of predicting potential improvement in water quality due to Best Management Practice (BMP) implementation. (2) It should assisted watershed planners in deciding which BMP implementation scheme is best for the watershed, and define high priority sub-basins in the watershed for implementation of BMPs. (3) The package should be able to predict water quality changes in streams receiving irrigation return flow, and predict possible adverse effects in the streams due to a certain mix of BMP implementation schemes. (4) The model should be based on physical processes and usable for other surface-irrigated watersheds. The study area is comprised of two watersheds, Rock Creek watershed south of Twin Falls, Idaho, and Cedar Draw watershed west of Filer, Idaho and to the east of Buhl, Idaho